A class I anti-arrhythmic agent (one that interferes directly with the depolarization of the cardiac membrane and thus serves as a membrane-stabilizing agent) with a depressant action on the heart similar to that of guanidine. It also possesses some anticholinergic and local anesthetic properties.

A class IA anti-arrhythmic agent with cardiac depressant property. Disopyramide blocks the fast sodium channel in normal cardiac cell membranes within atrial and ventricular tissues. This slows the rate and amplitude of phase 0 depolarization and thus prolongs the duration of the action potential, thereby reducing cell excitability and conduction velocity. Further, disopyramide directly decreases the rate of diastolic (phase 4) depolarization in cells with normal or augmented automaticity. Disopyramide also blocks potassium channel and results in prolonged QT interval, thus increases the effective refractory period. This agent also possesses anticholinergic property.

Class I antiarrhythmic agent (one that interferes directly with the depolarization of the cardiac membrane and thus serves as a membrane stabilizing agent) with a depressant action on the heart similar to that of guanidine; it also possesses some anticholinergic and local anesthetic properties.